The purpose of a motion control device is to move an object in a desired manner. The basic components of a motion control device are a controller and a mechanical system. The controller controls the mechanical system to move in a desired manner based on an application program comprising a sequence of instructions. While the mechanical system commonly comprises a drive and an electrical motor, other systems can be used to cause movement of an object based on a control signal. Additionally, it is possible for a motion control device to comprise a plurality of drives and motors to allow multi-axis control of the movement of the object.
Motion control devices are typically classified as general motion devices or computer numeric control (CNC) devices. General motion devices are general-purpose machines typically characterized by low cost controllers. CNC devices are relatively specialized, high level systems employing a high cost controller. The term “motion control system” will be used in the following discussion to refer to any system employing one or both of a general motion device and a CNC device. A motion control system is often used in conjunction with a host computer or programmable logic controller (PLC). The host computer or PLC allows the use of a high-level programming language to generate control commands that are passed to the controller. Application programs may be stored at various locations in a motion control system, including directly on the controller of a target device such as a general motion device or CNC device.
The present invention is of particular importance in the context of a motion control system in which multiple programming languages and language variants are used. Companies that manufacture motion control devices are, traditionally, hardware oriented companies that manufacture software dedicated to the hardware that they manufacture. These software products may be referred to as low-level programs. Low-level programs usually work directly with the motion control command language specific to a given motion control device. While such low-level programs offer the programmer substantially complete control over the hardware, these programs are highly hardware dependent.
In contrast to low-level programs, high-level software programs, referred to sometimes as factory automation applications, allow a factory system designer to develop application programs that combine large numbers of input/output (I/O) devices, including motion control devices, into a complex system used to automate a factory floor environment. These factory automation applications allow any number of I/O devices to be used in a given system, as long as these devices are supported by the high-level program. Custom applications, developed by other software developers, cannot be developed to take advantage of the simple motion control functionality offered by the factory automation program.
Additionally, these programs do not allow the programmer a great degree of control over the each motion control device in the system. Each program developed with a factory automation application must run within the context of that application.
The present invention also optionally has more specific application to an environment in which a general motion device is used to implement an application program written for a CNC device. The principles of the present invention are, however, generally applicable to any target motion control device that generates movement based on an application program.
A typical motion control system created for a particular task may use one or more application programs written in any number of different programming languages. The need thus exists for systems and methods that facilitate the generation of motion control commands in a multi-language environment. In addition, because of the relatively low cost of controllers for general motion devices, the need exists for systems and methods that convert programs written for CNC devices into control commands for general motion devices.